Metam-sodium

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Data is from peer reviewed journal

Justification for type of information:

Data is from peer reviewed journal

Qualifier:

according to guideline

Guideline:

other: as mention below

Principles of method if other than guideline:

Study was conducted to assess the effect of chemical on growth and survival of Euglena gracilis Z in the absence of light (dark) as well as in presence of light.

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material : Metam-sodium
- Molecular formula : C2H4NNaS2
- Molecular weight : 129.1826 g/mole
- Smiles notation : C(=S)(NC)[S-].[Na+]
- InChl : 1S/C2H5NS2.Na/c1-3-2(4)5;/h1H3,(H2,3,4,5);/q;+1/p-1
- Substance type: Organic
- Physical state: Solid

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Euglena gracilis

Details on test organisms:

Details on test organisms
TEST ORGANISM
- Common name: Flagellate Euglenoid
- Strain: Euglena gracilis Z
- Source (laboratory, culture collection): Indiana Culture Collection
- Method of cultivation: The organism was grown in the Euglena medium, pH 5.5 under constant illumination from fluorescent lamps with constant agitation at 22°C. The intensity of
illumination was 200 ft-C at the surface of the flasks. Cells were harvested and washed with fresh medium by centrifugation and used as an inoculum for experiments.

Test type:

static

Water media type:

freshwater

Total exposure duration:

9 d

Post exposure observation period:

After 5 days effect were also observed

Test temperature:

22°C

pH:

5.5

Nominal and measured concentrations:

0, 0.1, 1, 5 and 10 mg/l.

Details on test conditions:

Details on test conditions:
For the growth experiments, test chemical were added to the culture medium as aqueous solutions and thoroughly mixed before addition of the cells. Celt numbers were determined after the indicated times with a Coulter Counter Model B. Pesticide solutions were made freshly and filter sterilized before each experiment.

Reference substance (positive control):

not specified

Key result

Duration:

5 d

Dose descriptor:

other: IC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 88.7 % growth inhibition were observed in the light condition

Duration:

9 d

Dose descriptor:

other: IC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 54.6 % growth inhibition were observed in the dark condition

Fig: Effect of different concentration of chemical on Growth of. Euglena gracilis Z

Concentration in mg/l	% inhibition
	Light	Dark
10	95 %	86.5 %
5	99.6 %	84.4 %
1	88.7 %	54.6 %
0	9.4 %	24.6 %

 

Validity criteria fulfilled:

not specified

Conclusions:

Based on the growth rate inhibition and effect on the survival of Euglena gracilis (Flagellate Euglenoid), the inhibitory concentration was determine to be 1 mg/l in the absence and presence of light.

Executive summary:

Study was conducted to assess the effect of chemical on growth and survival of Euglena gracilis Z in the absence of light (dark) as well as in presence of light. Test conducted at 0, 0.1, 1, 5 and 10 mg/l concentration.

 

The organism was grown in the Euglena medium, pH 5.5 under constant illumination from fluorescent lamps with constant agitation at 22°C. The intensity of illumination was 200 ft-C at the surface of the flasks. Cells were harvested and washed with fresh medium by centrifugation and used as an inoculum for experiments. Celt numbers were determined after the indicated times with a Coulter Counter Model B.

 

Based on the growth rate inhibition and effect on the survival of Euglena gracilis (Flagellate Euglenoid), the inhibitory concentration was determine to be 1 mg/l in the absence and presence of light. Based on the effect observed chemical was consider as toxic as the 88 % toxicity were observed at the 1 mg/l so on that basis chemical was consider as toxic and classified as aquatic acute 1 as well as chronic 1 category as per the CLP classification criteria.

Description of key information

Study was conducted to assess the effect of chemical on growth and survival of Euglena gracilis Z in the absence of light (dark) as well as in presence of light. Test conducted at 0, 0.1, 1, 5 and 10 mg/l concentration. The organism was grown in the Euglena medium, pH 5.5 under constant illumination from fluorescent lamps with constant agitation at 22°C. The intensity of illumination was 200 ft-C at the surface of the flasks. Cells were harvested and washed with fresh medium by centrifugation and used as an inoculum for experiments. Celt numbers were determined after the indicated times with a Coulter Counter Model B. Based on the growth rate inhibition and effect on the survival of Euglena gracilis (Flagellate Euglenoid), the inhibitory concentration was determine to be 1 mg/l in the absence and presence of light. Based on the effect observed chemical was consider as toxic as the 88 % toxicity were observed at the 1 mg/l so on that basis chemical was consider as toxic and classified as aquatic acute 1 as well as chronic 1 category as per the CLP classification criteria.

Additional information

Based on the various experimental data and predicted data for the target chemical Metam-sodium (137-42-8) study have been reviewed to determine toxic nature of on the growth and other activity of invertebrates. The studies are as mentioned below: 

 

In the first key experimental study for the Metam-sodium (137-42-8) from peer reviewed journal (Bulletin of Environmental Contamination & Toxicology 1970), study was conducted to assess the effect of chemical on growth and survival of Euglena gracilis Z in the absence of light (dark) as well as in presence of light. Test conducted at 0, 0.1, 1, 5 and 10 mg/l concentration. The organism was grown in the Euglena medium, pH 5.5 under constant illumination from fluorescent lamps with constant agitation at 22°C. The intensity of illumination was 200 ft-C at the surface of the flasks. Cells were harvested and washed with fresh medium by centrifugation and used as an inoculum for experiments. Celt numbers were determined after the indicated times with a Coulter Counter Model B. Based on the growth rate inhibition and effect on the survival of Euglena gracilis (Flagellate Euglenoid), the inhibitory concentration was determine to be 1 mg/l in the absence and presence of light. Based on the effect observed chemical was consider as toxic as the 88 % toxicity were observed at the 1 mg/l so on that basis chemical was consider as toxic and classified as aquatic acute 1 as well as chronic 1 category as per the CLP classification criteria.

 

Similarly in the second experimental study for Metam-sodium (137-42-8) from secondary source Draft Assessment Report 2007 toxicity was measured on the growth of algae. Determination of the level of concentration at which it affects the growth of algae Pseudokirchneriella subcapitata (green alga). Test conducted according to the OECD Guideline 201: Alga, Growth Inhibition Test. Chemical was an analytically monetarized by HPLC with spectrophotometric detector. 96 hours study was performed under the static system on 1 x 104 cells/mL. 3 replicates for per concentration and 6 replicates for per control was used. Effect were measured after 72 hrs and 96 hrs. Based on the biomass rate inhibition of Pseudokirchneriella subcapitata by the chemical the EC50 was determine in range of 0.704 mg/l to 0.715 mg/l. On the basis of growth rate inhibition after 72 hrs EC50 was determined at 1.30 mg/l and after 96 hrs inhibition observed at 1.36 mg/l. Based on the EC50 (0.704 mg/l to 0.715 mg/l) test chemical was consider as toxic and concluded to be classified in aquatic acute 1 as well as chronic 1 category as per the CLP classification criteria.

 

Above studies was supported by another handbooks and authoritative database (Pesticide Properties Database) for the Metam-sodium (137-42-8). Study was conducted to assess the effect of chemical Metam-sodium on growth and survival of Pseudokirchneriella Subcapitata. After the chemical exposure for 72 hrs effect were observed on the growth of algae. Based on the growth rate inhibition of Pseudokirchneriella subcapitata due to the chemical Metam-sodium, the EC50 was determine to be 1.08 mg/l. based on the EC50 chemical was consider as toxic and can be consider to be classified as aquatic acute 1 as well as chronic 1 as per the CLP classification criteria.

 

Similarly in the fourth supporting data prediction done using the EPI Suite ECOSAR version 1.10, the short term toxicity on green algae was predicted for test substance Metam-sodium. On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance is estimated to be 0.55 mg/l for green algae for 96 hrs duration. Based on this value, it can be concluded that the test chemical Metam-sodium can be considered as toxic to green algae at environmentally relevant concentrations and can be considered to be classified in aquatic acute 1 / chronic category 1 as per the CLP classification criteria.

 

Based on the effect observed on the growth of aquatic algae and cyanobacteria, by the chemical Metam-sodium (137-42-8) from various experimental reports, it was conclude that the chemical was toxic and consider to be classified as aquatic acute 1 as well as chronic 1 category as per the CLP classification criteria.